For those who’re going to willy-nilly divide issues by random deflators, perhaps it’s best to learn this (free) manual first.
For a extra compact exposition, see this 2008 blogpost, with hyperlink to Diewert JEP piece.
Should confess, after I first bumped into “Fisher ideally suited worth indices” as an undergraduate, I used to be befuddled. However I appreciated the information after I turned a analysis assistant.